Square Kilometre Array program report

The big news since the last SKA report is the successful Gemini/SKA MNRF bid (see the lead article in this issue). While final divisions have yet to be decided, at least $18M will be spent on Australian SKA research over the next five years. The main SKA threads of the MNRF submission were the construction of two SKA demonstrators, the development of important enabling technologies for the SKA, and the establishment of a supercomputer facility to support astronomy and engineering simulations needed in designing the SKA. The ATNF and the University of Sydney will undertake the SKA demonstrator work, while Swinburne University of Technology will lead the SKA simulation activities. Enabling technologies will be developed by the ATNF and CSIRO Telecommunications and Industrial Physics (CTIP), in collaboration with initial industry partners such as CEA Communications and Advanced Powder Technologies.

The exact form of the SKA demonstrators is still to be decided. However, full use will be made of existing telescopes and infrastructure at Molonglo and Narrabri. In the case of the ATCA, a prime deliverable will be a new wideband digital correlator which, as well as being of enormous scientific value to users of the recently upgraded instrument, will form the heart of the ATNF SKA demonstrator.

One suggestion for the ATCA demonstrator involves the provision of two additional SKA mini-stations placed on an extended north-south baseline. Each station may be equivalent in area to a ~15-m dish, but each would be based on multi-beaming antennas _ such as Luneburg Lenses or phased arrays. Discussion over coming months will address the exact form of the demonstrator and it is likely that a final technology choice will be made by the end of 2002. (A discussion relating to the science with the ATCA demonstrator is scheduled for 6 November, at Marsfield).

While all existing SKA activities will continue, a number of new projects are planned. In particular, an integrated RF systems project and a phased array antenna project will be important constituents of the expanded CSIRO program. We also expect to have to manage many more industry and related research and development links as a number of potentially key SKA technologies can only be realistically developed in partnership with others. The Australian SKA Consortium (ASKAC), which has been active since early 2001, will be an important body in coordinating CSIRO and other Australian SKA work. ASKAC will also be represented formally on the Board of Management of the new MNRF.

The MNRF development has been exciting but work has also continued on a number of technical fronts in recent months. We have taken delivery of the 0.9-m Russian Luneburg Lens, described in the last ATNF News and, in conjunction with CTIP, have been assessing its performance using near- and far-field testing procedures. First results indicate good beamforming properties but precision tests to establish absolute gain and dielectric loss have proved quite challenging. However, the testing program is now close to completion. Having a real lens to assess has proved extremely useful and will, no doubt, be of lasting value in framing our design and analysis methodology for prototype Australian lenses. New links are currently being forged between various CSIRO and industry partners; these collaborations may deliver the artificial dielectrics that are central to the manufacture of low loss, low cost, lenses.

As well as the lens antenna work, the ATNF is also expanding activities in the area of phased arrays. In collaboration with CTIP and ASTRON colleagues, we will shortly take delivery of a Dutch "egg-crate" Vivaldi horn array (similar to the THEA units). This will be used initially for experiments with the 0.9-m Luneburg Lens and as the antenna section of our first integrated RF assemblies.

Other major activities over the past few months include reduction of first Western Australia site test data; Bruce Thomas has provided a separate update elsewhere in this newsletter. Our Australian group was also very active and visible at the Berkeley SKA "Defining the Future" gathering. Full proceedings (including poster papers) are available on the Web at http://www.skatelescope.org /skaberkeley/.

On the local front, ASKAC met in Adelaide (South Australia) on October 4. The previous day was devoted to an SKA Science and Engineering Symposium; proceedings will shortly be available at http://www.atnf.csiro.au/SKA/Aust_SKA_Symp_Home_Oct01.html .

An increased industry presence was especially welcome at this gathering, as was South Australian political and government agency representation.

Peter Hall
(Peter.Hall@csiro.au)